Imbalances in Faecal Bifidobacterium species in Coeliac Disease
Since the advent of culture-independent techniques for the assessment of faecal microbiota, many studies have emerged seeking to examine the relationship between faecal microbiota and specific diseases, such as eczema1 and Crohn’s Disease2. Once such example is the association between imbalances in the intestinal microbiota and celiac disease (CD). In particular, a lot of attention has focused on the possible role of Bifidobacterium species.
It is common knowledge that the Bifidobacterium genus constitutes an important bacterial group in the human gut, where it is thought to be essential to maintain health via beneficial metabolic, trophic, and protective functions.3, 4 Bifidobacterium is the predominant intestinal bacterial genus during the first year of life, with differences in total bifidobacterium levels and Bifidobacterium species thought to be linked to children with allergic/atopic conditions such as eczema.5-7
Qualitative and quantitative differences in Bifidobacterium species composition have also been related to the development of inflammatory disease such as irritable bowel syndrome, inflammatory bowel diseases (IBD) and colorectal cancer compared to healthy controls.9 What’s even more fascinating is that different immunomodulatory properties have been attributed to different Bifidobacterium species that in turn have been related to different disease risks. For example, strains of B. adolescentis have been shown to be more proinflammatory or have non-effect on immunity, while strains of the species B. bifidum and B. longum were shown to have immunoregulatory properties.10-12 In keeping with this, it has been suggested that Bifidobacterium strains colonizing the human gut could affect the balance of T-helper 1 (Th1)/Th2 lymphocyte responses to exogenous antigens related to either allergic diseases (characterized by a Th2 phenotype polarization) or Crohn and CD (characterised by a Th1 phenotype polarization). With this in mind, researchers the Microbial Ecophysiology and Nutrition Group Institute of Agrochemistry and Food Technology in Spain set out to assess the possible relationships between the gut bifidobacteria composition and CD in children.13
The researchers obtained a total of 48 faecal samples made up of 30 samples from active CD patients and 18 from non-active CD patients. These samples were compared with 30 faecal samples from a control age-matched group of children. Each sample was subject to real-time PCR analysis using genus and species probes for Bifidobacterium.
On analysis of the results, active and non-active CD patients showed lower numbers of total Bifidobacterium and B. longum species in faeces compared to controls, with the differences most significant between active CD patients and controls. The authors concluded that these bacterial groups could constitute novel targets for adjuvant dietary therapies in CD.
References
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